Electrolytes for magnesium-ion batteries

ABSTRACT

Disclosed is a class of organic salts and electrolytes, generally for use with electrochemical devices. Some of these salts enable the transport of magnesium ions without the presence of any additives, such as halide ions. Precursors are generated using simple fluorinated alcohols as well as abundant reagents. These precursors, often dissolved in ethereal solvents, may be combined with an appropriate Lewis acid to result in solutions that are able to conduct ions and allow for reversible electrodeposition.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of U.S. Provisional Application Nos.62/140,599 and 62/140,983, both filed Mar. 31, 2015, and U.S.Provisional Application No. 62/300,471, filed Feb. 26, 2016 which arehereby incorporated in its entirety by reference.

BACKGROUND OF THE INVENTION

Nonaqueous magnesium ion batteries that use a metallic magnesium anodeare attractive due to their high theoretical volumetric energy densityand comparatively low cost of materials compared to lithium ion systems.Studies incorporating Grignard-based electrolytes for magnesiumelectrodeposition date back to the early twentieth century, but theiruse as electrolytes for magnesium batteries became of interest only asrecently as 1990. Aurbach et al. studied electrolyte solutions that weresynthesized by reacting an alkylmagnesium halide or a dialkylmagnesiumspecies with a Lewis acid of general structure R_(x)AlCl_(3-x). Thecomplex species that result are capable of reversible magnesiumelectrodeposition, yet Barile et al. showed that these types of adductsdecompose as a function of cycle count, based on NMR and GC-MS of theelectrolyte and on SEM-EDS analysis of the electrodeposited metal. Assuch, the development of other, more suitable electrolytes forreversible magnesium electrodeposition is paramount.

BRIEF SUMMARY OF THE INVENTION

The present invention discloses a composition of matter represented bythe formula M(OR)₂, wherein R is represented by the formula CR₁R₂R₃ andR₁, R₂, and R₃ independently represent a hydrogen atom, a halogen atom,or a substituted or non-substituted hydrocarbyl, haloalkyl or haloarylgroup; wherein M is an alkaline earth metal; and wherein R is comprisedof at least one hydrogen atom and at least one halogen atom.

Also disclosed is a composition of matter substantially represented bythe formula M₁(M₂R′_(n)R″_(m))₂, wherein n+m=4, M1 comprises an alkalineearth metal, M2 comprises a Group III metal, and R′ and R″ areindependently fluorinated or non-fluorinated moieties.

Also disclosed is an electrolyte precursor represented by the formulaMgR₂, wherein R is a halogenated alkoxide.

A method for generating a precursor is also disclosed, involvingcombining a first material, comprising at least one of a magnesiumdialkoxide, magnesium diaryloxide, magnesium metal, magnesium alloy,Mg(OH)₂, MgH₂, or any dialkyl magnesium species with a second material,comprising a halohydrin or a fluorinated alcohol. The precursor may alsobe combined with a secondary component to form an electroactiveelectrolyte.

A solvated electroactive electrolyte is also disclosed, comprising asolvated cation species, represented by the formula MgR₂, wherein R is afluorinated or non-fluorinated moiety; an anion; and an etherealsolvent.

Further disclosed are electrochemical devices, comprising an anode; acathode; and an electrolyte solution, wherein the electrolyte solutioncomprises either a solvated electroactive electrolyte, an electrolyteprecursor, or a compound represented by the formula MR, wherein R is ahalogenated alkoxide and M is an alkali metal.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram of one embodiment of an electrochemical device.

FIG. 2 is a graph of coulombic efficiency versus number of cycles for anembodiment of an electrochemical device.

FIG. 3 is a representative cyclic voltammogram of an embodiment of anelectrochemical device.

FIG. 4 is a graph of oxidative stability measured on a variety ofdifferent electrode materials

DETAILED DESCRIPTION OF THE INVENTION

The present invention generally discloses an electrolyte or electrolyteprecursors that enables reversible electrodeposition, includingmagnesium electrodeposition, and electrochemical devices that utilizethese electrolytes or precursors.

More specifically, the invention discloses a composition of matter,represented by the formula M(OR)₂. R is comprised of at least onehydrogen atom and at least one halogen atom, and is represented by theformula CR₁R₂R₃. R₁, R₂, and R₃ independently represent a hydrogen atom,a halogen atom, or a substituted or non-substituted hydrocarbyl,haloalkyl or haloaryl group. M is an alkaline earth metal.

In one embodiment, the haloalkyl or haloaryl groups are fluoroalkyl orfluoroaryl groups. In another embodiment, R is a C₁-C₁₁ fluoroalkyl orfluoroaryl that is unsubstituted, or alternatively, substituted with oneor more heteroatom linkers. In that embodiment, R is preferably atrifluoroethyl, hexafluoro-iso-propyl, or hexafluoro-2-phenyl-2-propylgroup and derivatives thereof. In yet another embodiment, the preferredalkaline earth metal is magnesium.

Some examples of preferred embodiments include:

and Magnesium 1,1,1,3,3,3-hexafluoro-2-phenyl-2-propoxide [Mg(HFPh)₂]:

One skilled in the art will recognize that, while the above examplesillustrate variations of a preferred embodiment, similar embodimentsutilizing other alkaline earth metals are envisioned.

The present invention also discloses a composition of matter,substantially represented by the formula M1(M2R′_(n)R″_(m))₂, whereinn+m=4, M1 comprises an alkaline earth metal, M2 comprises a Group IIImetal, and R′ and R″ are independently fluorinated or non-fluorinatedmoieties. The fluorinated or non-fluorinated moieties include, but arenot limited to alkyl, fluoroalkyl, alkoxy, fluoroalkoxy,hexamethyldisilazane (HDMS), or bis (trifluoromethane)sulfonimide (TFSI)moieties. One preferred embodiment utilizes Mg as M1 and Al as M2. In amore preferred embodiment, R′ and R″ are equivalent moieties. And in aneven more preferred embodiment, R′ and R″ are equivalent fluoroalkoxymoities.

The present invention also discloses an electrolyte precursorrepresented by the formula MgR₂, wherein R is a halogenated alkoxide.The halogenated alkoxide may be a fluorinated alkoxide, and morespecifically, may be trifluoroethoxide, hexafluoro-iso-prop oxide, orhexafluoro-2-phenyl-2-prop oxide. Thus, examples of these electrolyteprecursors include, but are not limited to, Mg(TFE)₂, Mg(HFIP)₂, andMg(HFPh)₂.

In another embodiment, the halogenated alkoxide is substantiallyrepresented by the formula M1(M2R′_(n)R″_(m))₂, wherein n+m=4, M1comprises an alkaline earth metal, M2 comprises a Group III metal, andR′ and R″ are independently fluorinated or non-fluorinated moieties. Thefluorinated or non-fluorinated moieties include, but are not limited toalkyl, fluoroalkyl, alkoxy, fluoroalkoxy, hexamethyldisilazane (HDMS),or bis (trifluoromethane)sulfonimide (TFSI) moieties. One preferredembodiment utilizes Mg as M1 and Al as M2. In a more preferredembodiment, R′ and R″ are equivalent moieties. And in an even morepreferred embodiment, R′ and R″ are equivalent fluoroalkoxy moities.

Further disclosed is a method for generating an electroactiveelectrolyte. This method requires generating an electrolyte precursor.The method for generating a precursor is also disclosed, involving atleast one of three reaction paths.

The first reaction path is to combining a first material, comprising atleast one of a magnesium dialkoxide, magnesium diaryloxide, magnesiummetal, magnesium alloy, Mg(OH)₂, MgH₂, or any dialkyl magnesium specieswith a second material, comprising a halohydrin or a fluorinatedalcohol. The magnesium dialkoxide may include, but is not limited to,magnesium methoxide, magnesium ethoxide, magnesium isopropoxide, ormagnesium tert-butoxide. The halohydrin may include, but is not limitedto, trifluoroethanol, hexafluoro-iso-propanol, orhexafluoro-2-phenyl-2-propanol.

Although the invention is not limited to this embodiment, one preferredreaction scheme is: Mg(OCH₃)₂+2ROH->Mg(OR)₂+CH₃OH. Typical parentstarting alcohols may include numerous primary, secondary, or tertiaryalcohols, which include but are not limited to the following: CF₃CH₂OH;(CF₃)₂CHOH; (CF₃)₂COHPh; CFH₂CH₂OH; CF₃(CF₂)_(n)CH₂OH, where n=1 to 9;CF₃CHOHCH₂CH₃; and (CF₃)_(n)CH_(3-n)COH, where n=1 or 2. Alternatively,diols, including hexafluoro-2,3-bis(trifluoromethyl)-2,3-butanediol, orpolyether substituted fluoroalcohols, includingHOC(CF₃)₂CH₂(OCH₂CH₂)₂OMe, may also be utilized.

Typically, these precursors are produced in the presence of a solventsuch as toluene, or an ethereal solvent, which may include, but is notlimited to, tetrahydrofuran, dimethoxyethane, and higher order glymes,such as diglyme, triglyme, tetraglyme, or a combination of thesematerials.

The method for generating a precursor may also involve a recovery step.It may be possible to recover at least some alcohol resulting from thegeneration of the precursor. This material may then be used elsewhere ifdesirable; preferably, it would be recycled as a feed stream forgenerating additional precursors.

Example 1 Synthesis of Mg(HFIP)₂ Via Bu₂Mg

A solution of hexafluoroisopropanol (13.72 g, 2 eq) in THF (20 mL), waspurged with argon, transferred to a second flask, and chilled to 0° C.Di-n-butylmagnesium (1M in heptane, 33.0 mL, 1 eq) was added dropwisevia syringe to the chilled hexafluoroisopropanol solution; a whiteprecipitate formed and gas was evolved. The reaction mixture was removedfrom the ice bath and stirred for 12 hours. The solvent was removed invacuo, resulting in a residual white powder.

Example 2 Synthesis of Mg(HFIP)₂ from Mg Methoxide

A solution of 6-10 wt. % magnesium methoxide in methanol (30 mL, 1 eq)was added to a flask and the methanol was removed in vacuo. AnhydrousTHF (20 mL) was added to the flask. Hexafluoroisopropanol (9.3 mL, 2.2eq) was added to the flask, forming a clear, colorless solution. Thesolution stirred for 2 hours and filtered. The remaining solvent wasremoved in vacuo, and a residual white powder remained.

One skilled in the art will recognize that although these examplesutilize magnesium as the alkaline earth metal, that other alkaline earthmetals will function in a similar fashion, and these methods willproduce analogous electrolytes and precursors using alternative alkalineearth metals.

The second disclosed reaction path for generating a precursor involvessynthesis of a alkaline earth metal—Group III metal complex. A preferredembodiment is a magnesium species with an aluminum species. A morepreferred embodiment is a magnesium fluorinated dialkoxide with afluorinated aluminum alkoxide.

The second path can be substantially represented by the followingequation: M1R′₂+2M2R″₃→M1(M2R′_(n)R″_(m))₂, wherein n+m=4, M1 comprisesan alkaline earth metal, M2 comprises a Group III metal, and R′ and R″are independently fluorinated or non-fluorinated moieties, including butnot limited to alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, HDMS, or TFSI.A preferred embodiment utilizes Mg as M1 and Al as M2; the synthesisroute is then MgR′₂+2AlR″₃→Mg(AlR′_(n)R″_(m))₂, where n+m=4, and R′ andR″ are independently fluorinated or non-fluorinated moieties, includingbut not limited to alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, HDMS, orTFSI. In a more preferred embodiment, R′ and R″ are equivalent moieties;the synthesis route is then MgR₂+2AlR₃→Mg(AlR₄)₂.

While not limited to such an embodiment, the alkalike earth metalreactant as used here is preferably formed utilizing the first reactionpathway described above. Similarly, while the Group III metal reactantdoes not require any specific synthesis route, preferred embodimentsinclude but are not limited to:

Al(metal)+3R′→Al(R)₃

Al(metal)+3R′(in presence of amalgam, e.g., Ga—In eutectic)→Al(R)₃

Al(metal)+3R′(in presence of I₂)→Al(R)₃

Me₃Al+3R′→Al(R)₃

Al(OH)₃+3R′→Al(R)₃+3H₂O(removed by e.g. molecular sieves)

Where R is a fluoroalkoxide or fluoroaryloxide, including but notlimited to trifluoroethoxide, hexafluoroisopropoxide (HFIP), orperfluorotertbutoxide, and R′ is the fluorinated alcohol correspondingto R, including but not limited to trifluoroethanol,hexafluoroisopropanol, or perfluorotertbutanol.

One general equation utilizing this route to form magnesium aluminumcomplexes is Mg(OR)₂+2Al(OR)₃→Mg[Al(OR)₄]₂. While this reaction schemeutilizes a 1:2 stoichiometric ratio, other ratios are envisioned,including but not limited to a ratios of 1:1 or 1:3.

Example 3 Preparation of Al(HFIP)₃ from Trimethylaluminum

A solution of hexafluoroisopropanol (8 mL, 12.77 g, 4 eq) in THF (20mL), was purged with argon, transferred to a second flask, and chilledto 0° C. Trimethylaluminum (2M in toluene, 9.5 mL, 1 eq) was addeddropwise via syringe to the chilled hexafluoroisopropanol solution;vigorous gas evolution was observed. The reaction mixture was removedfrom the ice bath and stirred for 12 hours. The solvent was removed invacuo, resulting in a white powder.

Example 4 Preparation of Several Mg(Al(OR)₄)₂ Solutions

Solutions of several of these adducts (ca. 0.25 M) were made by adding 2mL of a pre-prepared Al(OR)₃ solution to a vial containing the Mgspecies. Electrolyte solutions were then stirred for a minimum of 24hours, resulting in a clear and colorless solution.

The third reaction path can be substantially represented by theequation: 2M3M2R₄+M1X_(2→)M1(M2R₄)₂+2M3X, wherein X is a halogen, M1comprises an alkaline earth metal, M2 comprises a Group III metal, M3 isan alkali metal, and R is a fluorinated or non-fluorinated moiety,including but not limited to alkyl, fluoroalkyl, alkoxy, fluoroalkoxy,HDMS, or TFSI. An example utilizing the third reaction pathway, whichincludes the formation of a Group III-alkali metal compound is asfollows:

LiAlH₄+4ROH→LiAl(OR)₄+4H₂⇑  a)

2LiAl(OR)₄+MgCl₂→Mg[Al(OR)₄]₂+2LiCl⇓  b)

Where R is a fluorinated or non-fluorinated moiety.

The above described reactions can occur in appropriate solvents,generally leading to an electrolyte solution. Appropriate solventsinclude, but are not limited to: (1) ethereal solvents, including butnot limited to tetrahydrofuran, dimethoxyethane, diglyme, triglyme,tetraglyme, or other Lewis basic solvents; or (2) carbonate esters,including but not limited to ethylene carbonate or dimethyl carbonate.In one embodiment, fluorinated aluminum alkoxides and aryloxides can bedissolved in ethereal solvents, and can then be combined with secondarycomponents such as magnesium fluorinated alkoxides to result insolutions that are capable of reversibly electrodepositing magnesiummetal on metallic substrates. Additionally, catalytic amounts of MgCl₂or AlCl₃ can be added to activate the metal electrode and improveperformance.

In one embodiment, halide-ion free electrolytes are produced through“green” chemistry, using this simple synthesis route. The startingmaterials are inexpensive and the two components are very easy tosynthesize at scale.

The present invention also discloses a solvated electroactiveelectrolyte. This requires at least an anion, an ethereal solvent, and asolvated cation species represented by the formula MgR₂, wherein R is afluorinated or non-fluorinated moiety, including but not limited toalkyl, fluoroalkyl, alkoxy, fluoroalkoxy, HDMS, or TFSI. In oneembodiment, the fluorinated or non-fluorinated moiety is a halogenatedalkoxide. In another embodiment, the anion comprises a speciesrepresented by the formula AlR′₃, wherein R′ is a fluorinated ornon-fluorinated moiety, including but not limited to alkyl, fluoroalkyl,alkoxy, fluoroalkoxy, HDMS, or TFSI.

The electroactive electrolyte is generally prepared by combining aprecursor with a secondary component. Secondary components may includeany material that reacts with the precursor to generate an electroactiveelectrolyte, which includes but is not limited to: Lewis Acids such asAlCl₃, MgCl₂; a solid surface, including materials comprising an anodeor cathode, or a solid hydrocarbon, including but not limited toanthracene; and other elements, such as iodine.

Example 5 Preparation of Several MgR₂:AlCl₃ Solutions

Solutions of several of these adducts (ca. 0.25 M) were made by adding 2mL of a pre-prepared AlCl₃ solution to a vial containing the Mg species.

Electrolyte solutions were then stirred for a minimum of 24 hours. Ifany solid precipitates formed from the reaction, the solution wasfiltered before use.

All magnesium dialkoxides and diaryloxides in this example are white,free flowing powders, and are safer to handle than traditional magnesiumelectrolyte precursors, which are typically pyrophoric liquids.

The magnesium fluorinated alkoxides are generally soluble in etherealsolvents, and become more soluble with the addition of a material suchas AlCl₃.

Further disclosed is an electrochemical device. As illustrated in FIG.1, the generally requires an anode 20, a cathode 30, and an electrolytesolution 40. The composition of the electrolyte solution will typicallyinvolve a solvated electroactive electrolyte, such as those definedpreviously, although such is not required. The solution may insteadcomprise an electrolyte precursor, such as those defined previously.Alternatively, the solution may comprise a compound represented by theformula MR, wherein R is a halogenated alkoxide and M is an alkalimetal, including but not limited to LiTFE or NaHFIP. It is expected thatthe electrolyte precursors and compounds represented by the formula MRmay also be used as additives in electrolyte solutions.

Stabilizers can be added to improve performance within anelectrochemical device. To stabilize an electrolyte solution, a quantityof a stabilizer can be added and combined with the electrolyte solution.Stabilizers are typically solid polycyclic aromatic hydrocarbons. In oneembodiment, anthracene can be used as an activator and stabilizer foruse in magnesium ion batteries, regardless of the composition of theelectrolyte.

In addition to other uses, the electrochemical device may be configuredto operate as a battery. As a battery, the cathode may comprise avariety of materials, but in a preferred embodiment, the cathodecomprises at least one of elemental sulfur; a sulfur compound; aChevrel-phase compound; a conversion type or an intercalation typecompound, including conventional cathode materials such as Mo₆S₈. Theanode may comprise magnesium metal or a magnesium-containing alloy. Oneexemplary electrochemical device comprises a magnesium anode, a Mo₆S₈cathode, and an electrolyte solution comprising 0.5 M Mg, 1:1Mg(hexafluoroisopropoxide)₂:AlCl₃.

Some embodiments of the electrochemical device exhibit high platingcoulombic efficiency. Preferably, the device has an efficiency after 50cycles that exceeds 90%, and more preferably, the efficiency after 100cycles exceeds 95%.

Measurement of the coulombic efficiency is performed by running a cyclicvoltammogram on a 2032 coin cell using an Mg anode, copper or platinumcathode, and a separator. The voltammogram starts at 0 V, scans to ca.−0.5 V, scans to 1 V, and returns back to 0 V. This constitutes onecycle, and the process is performed at 10 mV/s. A representativevoltammogram of the 300th cycle of one embodiment of the presentinvention is shown in FIG. 3. The efficiency is calculated by taking theintegral of the oxidative stripping peak divided by the integral of thereductive plating peak and multiplying by 100. This process is performedusing a potentiostat at room temperature in an inert atmosphere.

One exemplary device comprises a magnesium anode, a platinum cathode,and an electrolyte solution comprising 0.5 M, 1:1 Mg(HFIP)₂:AlCl₃. Thisdevice exhibits a 200 mV plating overpotential, and a 98% platingcoulombic efficiency at 10 cycles and maintains that efficiency for atleast 100 cycles.

Another exemplary device uses the same solution described above, bututilizes a copper cathode, a magnesium anode, and a separator. Thisdevice exhibits a plating overpotential of 200 mV, and as shown in FIG.2, approximately 100% plating efficiency after 25 cycles, maintainingthat level of efficiency for the remainder of the test period.

Utilizing these electrolytes and precursors in certain concentrationscan allow the electrolytic solution to exhibit a useful range ofconductivities. In certain embodiments of the present invention, theconductivity of the device electrolyte ranges from about 3 mS/cm toabout 10 mS/cm. One exemplary electrolyte solution comprising 0.25 M 1:1Mg(HFIP)₂:AlCl₃ in DME has a conductivity of 5.3 mS/cm. Anotherexemplary electrolyte solution comprising 0.25 M 2:1 Mg(HFIP)₂:AlCl₃ inDME as a conductivity of 4.5 mS/cm. A third exemplary solutioncomprising 0.25 M 1:2 Mg(TFE)₂:AlCl₃ in DME has a conductivity of 3.4mS/cm. A fourth exemplary solution comprising 0.25 M 1:2 Mg(HFIP)₂:AlCl₃in DME has a conductivity of 9.1 mS/cm.

It is well known that poor oxidative stability limits the types ofcathode materials that can be used in a full battery cell. Generally,the oxidative stability limit is defined as the onset of anodic currentflow. Also disclosed are embodiments where the oxidative stability ofthe electrolyte solution ranges from about 2.5 V to about 3.5 V vs. Ptelectrode. This measurement is accomplished by submerging a metalelectrode (generally platinum, copper, stainless steel, and otherrelevant metals used in batteries) into an electrolyte solution.Magnesium foil is used as both a counter and reference electrode. Then,the voltage is swept from 0 V vs. Mg to more positive potentials, untilthe current density reaches 10 mA/cm². The voltage at which this currentdensity is reached defines the oxidative stability limit. This processis performed using a potentiostat at room temperature in an inertatmosphere.

One exemplary electrolyte solution comprising 0.25 M 1:2 Mg(HFIP)₂:AlCl₃in DME has an anodic stability limit of 2.78 V vs. Mg using a platinumworking electrode. Another exemplary electrolyte solution comprising0.25 M 1:2 Mg(TFE)₂:AlCl₃ in DME has an anodic stability limit of 3.22 Vvs. Mg using a platinum working electrode.

FIG. 4 discloses the oxidative stability of an electrolyte solutionusing a variety of different working electrodes. In FIG. 4, theelectrolyte solution comprises 0.25 M 1:2 Mg(HFIP)₂:Al(HFIP)₂ in DME,and tests were run utilizing copper, platinum, aluminum, and 304 and 316stainless steels working electrodes.

Various modifications and variations of the invention in addition tothose shown and described herein will be apparent to those skilled inthe art without departing from the scope and spirit of the invention,and fall within the scope of the claims. Although the invention has beendescribed in connection with specific preferred embodiments, it shouldbe understood that the invention as claimed should not be unduly limitedto such specific embodiments.

What is claimed is:
 1. A composition of matter, represented by theformula M(OR)₂, wherein R is represented by the formula CR₁R₂R₃ and R₁,R₂, and R₃ independently represent a hydrogen atom, a halogen atom, or asubstituted or non-substituted hydrocarbyl, haloalkyl or haloaryl group;wherein M is an alkaline earth metal; and wherein R is comprised of atleast one hydrogen atom and at least one halogen atom.
 2. Thecomposition of matter of claim 1, wherein the haloalkyl or haloarylgroups are fluoroalkyl or fluoroaryl groups.
 3. The composition ofmatter of claim 2, wherein R is a C₁-C₁₁ fluoroalkyl or fluoroaryl thatis unsubstituted, or alternatively, substituted with one or moreheteroatom linkers.
 4. The composition of matter of claim 3, wherein Ris a trifluoroethyl, hexafluoro-iso-propyl, orhexafluoro-2-phenyl-2-propyl group and derivatives thereof.
 5. Thecomposition of matter of claim 1, wherein M is Mg.
 6. A composition ofmatter substantially represented by the formula M1 (M2R′_(n)R″_(m))₂,wherein n+m=4, M1 comprises an alkaline earth metal, M2 comprises aGroup III metal, and R′ and R″ are independently fluorinated ornon-fluorinated moieties.
 7. The composition of matter of claim 6,wherein R′ and R″ are independently selected from the group consistingof alkyl, fluoroalkyl, alkoxy, fluoroalkoxy, hexamethyldisilazane, orhis (trifluoromethane)sulfonimide.
 8. The composition of matter of claim6, wherein M1 is Mg and M2 is Al.
 9. The composition of matter of claim8, wherein R′ and R″ are equivalent moieties.
 10. An electrolyteprecursor represented by the formula MgR₂, wherein R is a halogenatedalkoxide.
 11. The composition of matter of claim 10, wherein thehalogenated alkoxide is a fluorinated alkoxide.
 12. The electrolyteprecursor of claim 11, wherein the fluorinated alkoxide istrifluoroethoxide, hexafluoro-iso-propoxide, orhexafluoro-2-phenyl-2-propoxide.
 13. The composition of matter of claim10, wherein the halogenated alkoxide is substantially represented by theformula M2R′_(n)R″_(m), wherein n+m=4, M2 comprises a Group III metal,and R′ and R″ are independently fluorinated or non-fluorinated moieties.14. An electrochemical device, comprising: an anode; a cathode; and anelectrolyte solution, wherein the electrolyte solution comprises anelectrolyte precursor of claim
 10. 15. A method for generating aprecursor, comprising at least one of the following steps: combining afirst material, comprising at least one of a magnesium dialkoxide,magnesium diaryloxide, magnesium metal, magnesium alloy, Mg(OH)₂, MgH₂,or any dialkyl magnesium species with a second material, comprising ahalohydrin or a fluorinated alcohol; combining an alkaline earth metalspecies with a Group III metal species in a manner substantiallyrepresented by the chemical equation: M1R′₂+2M2R″₃→M1(M2R′_(n)R″_(m))₂,wherein n+m=4, M1 comprises an alkaline earth metal, M2 comprises aGroup III metal, and R′ and R″ are independently fluorinated ornon-fluorinated moieties; or combining an alkaline earth metal specieswith a Group III metal species in a manner substantially represented bythe chemical equation: 2M3M2R₄+M1X₂→M1(M₂R₄)₂+2M3X, wherein X is ahalogen, M1 comprises an alkaline earth metal, M2 comprises a Group IIImetal, M3 is an alkali metal, and R is a fluorinated or non-fluorinatedmoiety.
 16. The method of claim 15, wherein generating the precursoroccurs in the presence of an ethereal solvent.
 17. The method of claim16, wherein the ethereal solvent is comprised of at least one of thegroup of tetrahydrofuran, dimethoxyethane, and higher order glymes, suchas triglyme or tetraglyme.
 18. The method of claim 15, furthercomprising recovering at least some alcohol resulting from thegeneration of the precursor.
 19. The method of claim 15, wherein themagnesium dialkoxide is magnesium methoxide, magnesium ethoxide,magnesium isopropoxide, or magnesium tert-butoxide.
 20. The method ofclaim 15, wherein the halohydrin is trifluoroethanol,hexafluoro-iso-propanol, or hexafluoro-2-phenyl-2-propanol.
 21. A methodfor generating an electroactive electrolyte, comprising generating aprecursor by the method of claim 15, then further reacting the precursorwith a secondary component.
 22. A solvated electroactive electrolyte,comprising: a solvated cation species, represented by the formula MgR₂,wherein R is a fluorinated or non-fluorinated moiety; an anion; and anethereal solvent.
 23. The solvated electroactive electrolyte of claim22, wherein the anion comprises a species represented by the formulaAlR′₃, wherein R′ is a fluorinated or non-fluorinated moiety.
 24. Thesolvated electroactive electrolyte of claim 23, further comprising asolid polycyclic aromatic hydrocarbon.
 25. The solvated electroactiveelectrolyte of claim 24, wherein the solid polycyclic aromatichydrocarbon is anthracene.
 26. An electrochemical device, comprising: ananode; a cathode; and an electrolyte solution, wherein the electrolytesolution comprises a solvated electroactive electrolyte of claim
 22. 27.The electrochemical device of claim 26, wherein the device is furtherconfigured to operate as a battery.
 28. The electrochemical device ofclaim 27, wherein the cathode comprises at least one of elementalsulfur; a sulfur compound; a Chevrel-phase compound; a conversion typeor an intercalation type compound.
 29. The electrochemical device ofclaim 27, wherein the plating coulombic efficiency after 50 cyclesexceeds 90%.
 30. The electrochemical device of claim 27, wherein theplating coulombic efficiency after 100 cycles exceeds 95%.
 31. Theelectrochemical device of claim 27, wherein the conductivity of thedevice electrolyte ranges from about 3 mS/cm to about 10 mS/cm.
 32. Theelectrochemical device of claim 27, wherein the oxidative stability ofthe electrolyte solution ranges from about 2.5 V to about 3.5 V on a Ptelectrode and 3.5 V to about 5.0 V on an Al electrode.
 33. Anelectrochemical device, comprising: an anode; a cathode; and anelectrolyte solution, wherein the electrolyte solution comprises acompound represented by the formula MR, wherein R is a halogenatedalkoxide and M is an alkali metal.
 34. A method of improving orstabilizing the performance of an electrochemical device, comprising thesteps of: providing an electrolyte solution; providing a quantity ofanthracene; and combining the electrolyte solution with the anthracene.